Condenser



June 12, 1928.

J. O. GARGAN CONDENSER Filed Jan. 5, 1926 T 1 I I I I I I I I I I I I l I I I I I I Patented June 12, 1,923."

` UNITED STATES PATENT orricr..

lfll' 0. GARGAN, OF BROOKLYN, NEW YQRX, -SSIG'NOR TO BELL TELEPHONE LBO- RATAOEBIES, ENCORPGRATED, OF NE?? YGI'LK, N. Y., A CORPORATION OF NEW '25033.

- connexions.

Application filed January 5, 1928. Serial No. 79,283. f

rlhis invention relates to condensers.

An object of the invention is to provide a condenser adapted to' withstand high voltage.

Another object is to secu-re low minimum capacity in a hi h voltage condenser.

A further obyect is to provide an adjustable condenser suitable for compensating the inherent capzicity between electrodes of a space discharge tube.

The condenser of the invention may comprise one or more pairs of concentric plates of semiecylindrical iorin separated by an air dielectric. The kplates are mounted upon opposite ends oI-` an insulator adapted to withstand high voltages. One o the plates may be fixed and the other rotatable about an axis by a gear drive, so that fine adjust ments of its capacity may be eilected. The condenser of the invention is suited to many uses, butv is particularly ada ted to compensate the inherent capacity o space discharge tubes, especially high power tubes.

The invention is illustrated in the drawing, wherein:

'Fig 1 is,a complete side View of a con.- denser designed in accordance with the invention. i

Fig. 2 is a plan. view of shown in Fig. 1.

Fig. 3 shows diagrammatically in cross section 4the relative position of the plates.

Fig', 4 illustrates diagrammatically in cross section a condenser designed in accord ance with the invention having a plurality of pairs ot plates. i

ln the several ligures of the drawing, like reference characters have been used to indicate like parts.

The condenser shown in Figs. 1 and 2 comprises an inner semi-cylindrical plate and an outer semi-cylindrical plate 11 arranged coa-xially andfattached to opposite the condenser ends of a cylindrical high 'voltage insulator 12. Plates 10 and 11 are mounted upon a base il ot insulating material adapted to withstand high voltages. 'When it is desired to ground the plate 10, the insulator 13 may be omitted and a conducting plate substituted therefor. rlie plate 10 and a terminal. 14 are fastened between the insulators 12 and l5 by a bolt 24;

The terminal 14 enables the plate 10 -to be connected to 'any electrical circuit.

The plate 11, is adapted to be rotated.

Attachedto the plate 11 is a helical gear 15. This gear meshes with a pinion 16 attached to a, shaft 17 provided with a knurlcd nut 18 or any other suitable means by which it may be rotated. The shaft 17 is jouriialed f in bearings provided in a supporting member 21. A terminal 30 is provided to enable the plate l1 to be connected to an electric circuit. The plate 11 is journaled upon a bearing 22 attached to the insulator 12 and is rotatable about a collar 23. The bearing 22 and the collar 23 are fastened to the insulator l2 by a bolt 181 provided with a nut 19. The supporting member 21 and the terminal member 30 are held on the bolt 181 between the collar 23 and the nut 19.

A coil spring Ais positioned around a portion of the collar 22 inside a recess in the gear 15 and is adapted to maintain a irm electrical connection between the plate 11 and the terminal member through the gear 15 and the supporting member 21.

As illustrated in Figs. 1 and 2 the plates are .in such position that thecapecity of the condenser is a. minimum. In general, high voltage condensers in use at the present time consist of a number of plates and a. number 'of high voltage insulators secured together in assembled 'relation by metallic screws or metallic bolts and nuts; with the results that these metallic elements introduce capacity effects supplementing that determined by the relative positions of the condenser plates. Hence, when the condenser plates are adjusted to produce a minimum Value of capacity, this value is determined in part by the plates and in part by the securing means.

In the condenser described above the number of insulating and conducting elements, including those necessary to the assembly, Yare reduced to a minimum. Again the securing bolts for each plate are spaced a considerable distance ,from the nearest portion of the o positelypcharged plate, and consequently the value of the capacity between these bolts is substantially negligible. When so constructed the value of the minimum capacity of the condenser will be determined solely by the lates and may be made as small as desire by designingthe condenser with relative great spacing of the plates and associated metallic mount-- ing members.

Fig. 3 is a diagram in cross section of plates l0 and ll showing late l() rotated It is found that if the surfaces of the plates of a condenser, to be subjected to highvoltages, are highly polished, the volt.- age at which break down occurs will be much higher than if the plates are unpolished. The Aplates of the'condenser herein described are soformed that their surfaces may be readily given a high polish. By virtue of this fact, this condenser is capable of withstanding increased voltages. Such condenser is suitable for use in high power radio transmitters for supplying a finely adjustable capacity adapted, tor example, to compensate the inherent interelectrode capacity of the spacedischarge tubes included in a high voltage circuit. i

Although., the platesare illustrated as semi-cylindrical in fornnit is quite evident that the curvatureemay be varied, and that by this means the rate of change of capacity with respect to angle 0I" rotation may be caused to follow several different laws.

Fig. 4 is a diagram in cross-section ot' a condenser similar in all respects to that illustrated in Figs. l, 2 and 3 except that two pairs of semi-cylindrical plates l0 and 1l are provided. By this means the capacity range of the condenser may be greatly increased and by including still other pairs of plates in the manner illustrated, the capacity range may be still further extended.

Although this invention has been illustrated in connection with certain specific embodiments, it is clear-that the principles involved may be applied to other forms and for this reason the invention is to be limited only as indicated by the scope of the appended claims.

lVhat is claimed is:

l. A condenser which comprises a lixed semi-cylindrical lindrical plate, a high voltage insulator, and means for attaching said plates to the opcurved plates of conducting material, a high volt-age insulator, means for securing said plates to the respective opposite ends of said insulator, which constitutes the sole physilcalconnection between said plateshineans for producing relative rotation ot said plates, a terminal member, and means for maintaining said terminal member electrically connected t o said rotatable plate.

4. A' condenser comprising, a pair of semi-cylindrical plates, a high voltage insulator, means for securing said plates to opposite ends of said insulator and for nia-intaining them spaced apart, said insulator constituting the sole physical connection between said plates, and means for rotating one of said plates relatively to the `other of said plates.

5. A condenser which comprises a plurality of fixed semi-cylindrical plates, a plurality of rotatable semi-cylindrical plates, said plates'being arranged coaxially, certain of said rotatable plates being adapted to move between certain of said lixed plates, a high voltage insulator, said tixed and rotatable plates being attached to opposite ends of said insulator, which constitutes the sole physical connection between said plates, and a gear for rotating said rotatable plates. l

In Witness whereof, l hereunto subscribe my name this 30th day of December A. D.,

plate, a rotatable seini-cy- 1925 JOHN GARGAN. 

